From these observations alone, what definite conclusions can be made?

Magneticfield pointsinto screen

s are positively charged, s negative.

Positive charged particles headed toward the earthfrom space, would tend (at mid-latitudes) to reach the surface coming down from the

A. NorthB. SouthC. EastD. WestE. split East and West

The Fantastic Four ®©1996 Marvel Comics

1900 Charles T. R. Wilson’s ionization chamber Electroscopes eventually discharge even when all known causes are removed, i.e., even when electroscopes are

•sealed airtight•flushed with dry,

dust-free filtered air

•far removed from any samples of

radioactivity•shielded with 2 inch thick

blocks of lead!

seemed to indicate an unknown radiation with greater penetrability than x-rays or

radioactive , , or rays

Speculating they might be extraterrestrial, Wilson ran underground tests at night in the Scottish railway, but

observed no change in the discharging rate.

1909 Jesuit priest, Father Thomas Wulf , improved the ionization chamber with a design planned specifically for high altitude balloon flights.

A taut wire pair replaced the gold leaf.

This basic design has became the pocket dosimeter radiation lab workers carry to record their total exposure to ionizing radiation.

0

1911-12 Austrian physicist Victor Hess, of the Vienna University, and 2 assistants, carried Wulf ionization chambers up in a series of hydrogen balloon flights.

• taking ~hour long readings at several altitudes • both ascending and descending

• radiation more intense above 150 meters than at sea level• intensity doubled between 1000 m to 4000 m• increased continuously through 5000 meters

In 1936, Hess was awarded the Nobel prize for this discovery.

Hess lands following a historic 5,300 meter flight. August 7, 1912National Geographic photograph

Dubbed this “high” level radiation Höhenstrahlung

Electroscopes became so robust, datacould be collected remotely (for example

retrieved from unmanned weather balloons)

1924 Walter Bothe and Geiger use multiple Geiger counters to establish the tracks followed by electron beams

1928-29 Bothe and Werner Kolhörster build Geiger telescopes and announce that cosmic “rays” contain charged particles

1927-28 Jacob Clay from Genoa to the Dutch colony of Java

•ionization intensity drops ~6% •minimum at magnetic equator

1929 Bothe & Kolhörster •suggest Clay’s Lattitude Effect was due to •deflection by earth’s magnetic field•primaries are charged

• inspired by the Norwegian mathematician Carl Størmer’s calculations explaining colleague Kristian Birkland’s theory of the aurora

• Birkland experimented with electron beams and a phosphorous-painted globe of lodestone

1930-33 Arthur Compton (University of Chicago) conductsa worldwide sea- and mountain-level lattitude survey of cosmic ray intensities and confirms the Latitude Effect.

The 4 curves correspond to 4 seasons. Physical Review 52 [1937]:p.808

1933-35 Thomas Johnson (of the Carnegie Institute) Bruno Rossi (Italy) independently mount

Geiger counter telescope arrays to test for an east-west asymmetry predicted by Georges Lemaître (Belgian)

Although cosmic rays do come “from all directions”,

at high altitudes near the equator the intensity is higher coming from

the West than from the East!

1939 Johnson speculates primaries may be protons!

Although cosmic rays do come “from all directions”,

at high altitudes near the equator the intensity is higher coming from

the West than from the East!

1939 Johnson speculates primaries may be protons!

50m

Cosmic ray strikes a nucleuswithin a layer of

photographicemulsion

Definite evidence for the celestial generation of CosmicRays came from fortuitous timing of a few high altitude balloon studies during some spectacular solar flares.

Unusual increase in cosmic ray intensity associated withan intense solar flare observed

February 28, 1942the same sunspot associated with this flare erupts again

March 7, 1942Similarly the

June 4, 1946 solar prominence

is followed by another eruptionJuly 25, 1946

and the solar flare event ofNovember 19, 1949

is also captured by airborne cosmic ray instrumentseach accompanied by a Sudden Ionospheric Disturbance

which interrupts radio communications on earth

What is the world’s most abundant element?

Oxygen O 46.6

Silicon Si 27.7

Aluminum Al 8.1

Iron Fe 5.0

Calcium Ca 3.6

Sodium Na 2.8

Potassium K 2.6

Magnesium Mg 2.1

Subtotal 98.5

Titanium Ti 0.4

Hydrogen H 0.1

Phosphorus P 0.1

Manganese Mn 0.1

Sulfur S 0.05

Carbon C 0.03

Total 99.3

CRUSTAL ABUNDANCE OF THE ELEMENTS (by % weight)

Average composition of clean, dry air at the Earth's surface

ConstituentSymbol

Molecular Weight

Molecular fraction

Fraction by mass

Nitrogen Oxygen Argon Carbon dioxide Neon Helium Methane Krypton Nitrous oxide

Hydrogen Ozone

N2 O2 Ar CO2

Ne He CH4 Kr N2O H2 O3

28 32 40 44

20 4 16 84 44 2 48

78.09 % 20.95 % 0.93 % 320 ppm

18 ppm 5.2 ppm 2.9 ppm 1.1 ppm 0.5 ppm 0.5 ppm 0.01 ppm

75.5% 23.2 % 1.3 % 486 ppm

12 ppm 0.7 ppm 1.6 ppm 3.2 ppm 0.8 ppm 0.03 ppm 0.02 ppm

Water, moisture

H2O 18 - -

Source: Garrels, MacKenzie and Hunt: Chemical cycles. 1975

Distribution of Elements in the Human Body (by weight)

Element Atomic no. Percentage Role

oxygen 8 65.0cellular respiration, component of water

carbon 6 18.5 basis of organic molecules

hydrogen 1 9.5component of water & most organic molecules, electron carrier

nitrogen 7 3.3component of all proteins and nucleic acids

calcium 20 1.5component of bones and teeth, triggers muscle contraction

phosphorus 15 1.0component of nucleic acids, important in energy transfer

potassium 19 0.4min positive ion inside cells, important in nerve function

sulfur 16 0.3 component of most proteins

sodium 11 0.2main positive ion outside cells, important in nerve function

chlorine 17 0.2 main negative ion outside cells

magnesium 12 0.1essential component of many energy-transferring enzymes

iron 26 traceessential component of hemoglobin in the blood

copper 29 trace component of many enzymes

molybdenum 42 trace component of many enzymes

zinc 30 trace component of some enzymes

iodine 53 trace component of thyroid hormone

Solar system massesSun 1.981030 kgJupiter 1.901027 kgEarth 5.981024 kg

Absorption “lines”

• First discovered in spectrum

of Sun (by an imaging scientist

named Fraunhofer)• Called “lines” because they

appear as dark lines super-

imposed on the rainbow of the

visible spectrum

Sun’s Fraunhofer absorption lines

(wavelengths listed in Angstroms; 1 A = 0.1 nm)

The Solar Spectrum

Emission line spectra

Insert various emission line spectra here

Emission line images

Planetary nebula NGC 6543

Green: oxygen; red: hydrogen(blue: X-rays)

Orion Nebula

The optical emission line spectrum of a young star

The Nuclear pp cycle

4 protons 4He + 6+ 2e

26.7 MeV

July 1969 Apollo 11 astronauts trap cosmic ray particles on exposed aluminum foil, returned to earth for analysis of its elemental & isotopic composition. With no atmosphere or magnetic field of its own, the moon’s surface is exposed to a constant barrage of particles.

March 3, 1972 Pioneer 10 launched -on its flyby mission, studies Jupiter's magnetic field and radiation belts.

December 1972 Apollo 17’s lunar surface cosmic ray experiment measured the flux of low energy particles in space (foil detectors brought back to Earth for analysis.

October 26, 1973 IMP-8 launched. Continues today measuring cosmic rays, Earth’s magnetic field, and the near-Earth solar wind from a near-circular, 12-day orbit (half the distance to the moon).

October 1975 to the present GOES (Geostationary Orbiting Environmental Satellite) An early warning system which monitors the Sun's surface for flares.

1977 The Voyager 1 and 2 spacecraft are launched. Each will explore acceleration processes of charged particles to cosmic ray energies.

August 31, 1991 Yohkoh spacecraft launched - Japan/USA/England solar probe - studied high-energy radiation from solar flares.July 1992 SAMPEX (Solar Anomalous and Magnetospheric Particle Explorer) in polar orbit. By sampling inter- planetary & magnetospheric particles, contributes to our understanding of nucleosynthesis and the acceleration of charged particles.

July 1992 IMAX (Isotope Matter-Antimatter eXperiment) balloon- borne superconducting magnetic spectrometer measured the galactic cosmic ray abundances of protons, anti-protons, hydrogen, and helium isotopes.

August 25, 1997 Advanced Composition Explorer (ACE) was launched!

Hydrogen (H) 1 1.00 640

Helium (He) 2 6.8 10-2 94

Lithium, beryllium, boron 2.6 10-9 1.5

Carbon, Nitrogen, Oxygen 1.2 10-3 6

Iron (Fe) 26 3.4 10-5 0.24

All heavier atoms 1.9 10-6 0.13

ElementAtomic

Number (Z)

Solar SystemComposition

(relative number of atoms)

PrimaryCosmic Ray

Flux(particles/m-2 sec)

50m

Cosmic ray strikes a nucleuswithin a layer of

photographicemulsion

A 1019 eV Extensive Air Shower

100 billion particles

at sea level

89% photons10% electrons~1% muons

12 km

6 km6 km

The Cosmic Ray Energy Spectrum

(1 particle per m2-sec)

(1 particle per m2-year)

(1 particle per km2-year)

Cosmic Ray Flux

Energy (eV)

Refrigerator cold CO2 bubble (887 mph)

0.02 eV

Room temperature nitrogen N2 (1160 mph)

0.03 eV

Atoms in sun’s MILLION DEGREE surface0.50 eV

Energy given to each single electron whenaccelerated by AA battery 1.5 eV

Electrons accelerated by your televisionpicture tube (traveling ~1/3 speed of light)

30,000 eV

Fermi National Lab’s high energy protons 1,000,000,000,000 eV

Superball bounced over your house 4 x 1017 eV

Pitched baseball 4 x 1020 eV

Slammed hockey puck 1 x 1021 eV

Recall: 1 joule = 6.2 x 1018 eV

The highest energy Cosmic Rays areSUBATOMIC particles carrying theenergy of MACROSCOPIC objects!

4 x 1021 eV = 60 joules

The Cosmic Ray Energy Spectrum

FERMILAB’s protonsFERMILAB’s protons

Bounced Superball

Bounced Superball

Pitched baseballPitched baseball

Hockey PuckHockey Puck

Energy (eV)

Two possible sources of cosmic rays

Colliding galaxies

Active galacticnucleus

GZK Cutoff

1966 - K. Greisen - G.T.Zatsepin & V.A.Kuz’min

showed the recently discovered cosmic microwave background radiation (CMBR)effectively makes the universe opaque tosufficiently high energy cosmic particles.

GZK Cutoff

For example:

p *+0 p

++ n

and similar resonances yield attenuation lengths mere 10s of Mega parsecs for cosmic ray protons with E>1019 eV.

Center of (our) Virgo supercluster is approximately 20 Mpc away

All E>1019 eV primaries must originate within 100 Mpc of the earth

1966 - K. Greisen - G.T.Zatsepin & V.A.Kuz’min

p

Energy [eV]

ICRC2001 news

AGASA: 717

HiRes: 7 2

events above 1020eV

AGASA